Hello everybody,

our homebuilding project have now reached the point where foils are becoming a real concern. Decks are being installed and the other small bits are being made or sourced.

I have researched costs of purchasing foils, but these are so expensive that I have to evaluate homebuilding before comitting to purchasing. I am sure commercially available foils are superior in quality and handling but I need to evaluate homebuilding.

Before deciding on materials and methods, I need a basic foil design for rudders and daggerboards.

The boat will be sailed in 2-up mode mostly and dominantly in 1 to 8 m/s windspeed. We assume normal crew weight.

As a rule of thumb the area of the daggerboards should be 2% of jib+mainsail according to some sources on the internet. Aspect ratio of 4 to 4.5 is considered "normal".

For daggerboards NACA0007 is a conservative choice. For rudders NACA0012 is a conservative choice.

Planform would be parallel leading and trailing egdes with a small diameter round-off at the leading egde bottom.


Have I got this mostly correct? Any comments and recommendations?